Comparison of activity and hsp -GFP expression data from the same fly at different ages. The data for tracking of the same fly over a period of 48 hours at different ages is overlaid to allow comparison of activity (upper panel; distance moved per hour) and GFP intensity (lower panel; average pixel intensity per hour). Black/white bars indicate the light/dark cycle the flies were cultured under prior to the beginning of the experiment. Different colors indicate the same fly at different ages (see Table 1). (A) hsp70-GFP transgenic fly, strain 2MI4, fly "a". Green, 32 days; Blue, 40 days; Black, 46 days; Red, 53 days. (B) hsp22-GFP transgenic fly, strain 1MI1, fly "b". Green, 32 days; Blue, 40 days; Black, 46 days. The 46-day old fly dies during the course of the experiment. Note: the overlap of the GFP intensity plots for the hsp22-GFP fly is not obvious because of the 18-hour period, however if this is taken into account the peaks are found to coincide.